In tuners of the related art that receive television broadcasts and the like, required specifications are set so that anticipated characteristics are even secured in severe reception environments such as when the signal strength of expected waves is weak, or the signal strength of interference waves is strong with respect to the signal strength of expected waves. However, there are many cases in which effective reception environments are not as severe as assumed. As a result of this, reception in a state in which a residue remains in the reception performance of the tuner is performed. Generally, since, in comparison with a case in which reception performance is low, electricity consumption is large in a case in which reception performance is high, there is a problem in that there is an excessive waste of electricity.
Furthermore, structures of emergency warning broadcasts (hereinafter, referred to as the Emergency Warning System: EWS as appropriate) for notifying viewers of emergency information by the receiver automatically starting up when disasters such as earthquakes and tsunamis have occurred, have been established. In digital broadcasts, the EMS is realized by incorporating a special start-up bit in the Transmission and Multiplexing Configuration Control (TMCC), and making use of transmission control information PSI (Program Specific Information). There is a problem in that even if the television receiver is not being viewed, in order to receive the EWS, it is necessary for the tuner to be in operation, and therefore, it is not possible to reduce the standby power of the television receiver due to the operation of the tuner.
PTL 1 discloses an adaptive modulation method that switches a modulation method depending on the status of a circuit, in which the electricity consumption is reduced by switching between two pathways that have different electricity usages as power amplification pathways.